geekguyandy wrote:The second bounce was only 3cm/s for 7 minutes, without much more movement. It now rests on it's side with one foot up. The batteries were in two systems - one which is sufficient for all the initial science data, and another that relies on solar power to extend the mission by several months, but they now fear that the final resting place next to a cliff wall will only provide 1.5hrs sun/day compared to the 6hr/day the planned landing site would have provided.

Can they shoot the harpoon to lift the lander while also tethering it to the comet, allowing it to "bounce" again when it rebounds at the end of the tether line and maybe land somewhere nearby that's better than its current location? Or even (if it would be useful, and possible... not quite sure how the physics work out here) hang out at the end of the tether line, being pulled along (or swung around) by the comet without actually being on its surface?

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For anyone who plays Kerbal Space Program - Scott Manley replicated the Rosetta mission in it, complete with landing. The video was recorded on Sunday, and it was strangely prophetic that his 'harpoon' failed as well: http://youtu.be/GlMRKKLGWlU

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What does the comet look like in true color? (I mean, after adjusting the brightness, since it has very low albedo)

Another thought: since the comet isn't that big, why didn't they give Philae a cord of 7km to wrap around it? It doesn't even have to be a strong rope, just enough to withstand the little bounces (specifically the stresses it causes in the rope) of the lander. Split the lander in two, cord in between and reel it in once the two halves are together again at the other side.

geekguyandy wrote:In the briefing they said that the first bounce (of nearly 2 hours) launched the craft up about 1km from the landing site, and because of the rotation of 67P and the angle of bounce, it translated about 1km away from the landing site. It initially hit at 1m/s (as planned) but the cold-gas thruster, harpoon system, and grappling system in the feet all failed, and the bounce resulted in a rebound of 38cm/s.

Argh, I hate extraterrestial motion. Normally, a vertical velocity of 38cm/s gets you 7mm off the ground for a total of 77ms "flight" time.Moreover, Rosetta was still millions of kilometres away when entering hibernation and it slept for two-and-a-half years.

Pfhorrest wrote:Can they shoot the harpoon to lift the lander while also tethering it to the comet, allowing it to "bounce" again when it rebounds at the end of the tether line and maybe land somewhere nearby that's better than its current location? Or even (if it would be useful, and possible... not quite sure how the physics work out here) hang out at the end of the tether line, being pulled along (or swung around) by the comet without actually being on its surface?

I hope they are going to try such a move, but not just yet. It would have quite a big risk of going over the escape velocity (1 m/s) and thus loosing Philae. In this position they can do some research, so I expect them to do that first. Once the battery level gets low enough that not much research can be done but the move is still possible I hope they try something to get Philae upright and in a better position. At that point not as much is lost by failing.

Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

Neil_Boekend wrote:It would have quite a big risk of going over the escape velocity (1 m/s) and thus loosing Philae.

That's why I was picturing the tether actually attaching to the comet as Philae is pushed away; when Philae reaches the end of the tether line, the line goes taut and Philae rebounds again, back toward the comet, to attempt another landing in a better position. Or depending on how far up the tether line can reach, and how quickly the comet is rotating (can the tether line reach out outside geos... er, uh, comet-o-synchronous orbit?), possibly swing Philae around at the end of the tether line, though I'm not sure Philae could do anything useful from that distance.

Yep, that is what one would hope to achieve. However, what happens if the tether doesn't hold? If they would attempt it now valuable research time would be lost. Better to try it when there isn't as much to lose.

Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

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Finally checking back in here to say, thanks for all the updates! It's like a curated news feed for all things Philae and Rosetta. I was gone all day at school and working on an extremely frustrating programming project, so I missed the updates about it bouncing and re-attaching. I'm still hoping for some space harpoon action. And thanks taixzo for the KSP video!

arcanmster wrote:Seems like they're going to drill without the harpoons, no much battery left...

60 hours of battery life isn't much, but here's to hoping it's enough. I'm a little concerned about how they're even gonna drill. They aren't anchored down and it certainly seems like Philae is sitting at an unstable angle.

geekguyandy wrote:The second bounce was only 3cm/s for 7 minutes, without much more movement. It now rests on it's side with one foot up. The batteries were in two systems - one which is sufficient for all the initial science data, and another that relies on solar power to extend the mission by several months, but they now fear that the final resting place next to a cliff wall will only provide 1.5hrs sun/day compared to the 6hr/day the planned landing site would have provided.

That's comet days, so almost 3 hours of sun per Earth day.

Poor thing. I start getting SAD around this time of year, but I should be grateful that at least I'm not directly solar powered.

May I just say: Damn you, Randall, for making me (and probably most of us) believe that Rovers and Landers have human feelings and emotions. I'm so sad that poor little Philae is lying on it's side, doing its job as good as it could.

Snagglepuss wrote:May I just say: Damn you, Randall, for making me (and probably most of us) believe that Rovers and Landers have human feelings and emotions. I'm so sad that poor little Philae is lying on it's side, doing its job as good as it could.

I think he was trying to portray Philae as more excited to be there, brave, not so heartbreaking as Spirit.

Snagglepuss wrote:May I just say: Damn you, Randall, for making me (and probably most of us) believe that Rovers and Landers have human feelings and emotions. I'm so sad that poor little Philae is lying on it's side, doing its job as good as it could.

I think he was trying to portray Philae as more excited to be there, brave, not so heartbreaking as Spirit.

It didn't work.

"Battery power running low. Can't charge using my solar panels. But I've got to send this drill results. A good robot would be able to send these results, a good robot like ESA wanted.""Hey Earth, did you get my transmission?""... can I go home now?""..."

There is a "writing prompt" on Reddit this morning, that you live on the comet and Rosetta is coming.I wrote a story vaguely based on the ramblings in this thread (and the comic itself). It was fun to write, even if it doesn't make much sense. I hope you enjoy it:

From the updates this morning, a woman from the battery team claimed that the solar panels and images now indicate that Philae is on all three lander feet, and has not moved since the first panorama was taken. I'm a bit confused how this is possible based on what was reported before. I'm guessing that the talk of drilling must mean that it's in a proper position as well. Now they just think it's located between a wall and a rock, and not receiving much solar power. There's a bad situation where the batteries have to be warm enough to be useful, but it takes power to warm them up of course. Currently it is not receiving enough light for this to happen, so it will likely run out of power and be unable to recharge.

geekguyandy wrote: Still no change on the image. Alt-text is still [LIVE]. Hmm

I don't know if it's worth a redraw or not, but based on what we've seen, I feel like Philae should be in a bit more of a crater / cave / not out in the open. Then again, we don't really know where he is. I hope he wakes up again, it would seem unresolved if he just fell silent to Rosetta's increasingly urgent calls. Especially after the 10 years they had together.

I hope there's a chance that they'll leave the lander sitting there for about a year (by then the comet is at its closest to the Sun) and then try bouncing up again and flying to a nice spot on top of a 'hill'. If that works out, Philae can try out its harpoons again and it can continue working for several years, if not decades.

Also, still waiting for a true color image of the comet. (with adjusted brightness)